This invention relates to an open-end spinning machine having a plurality of spinning units that are arranged next to one another and each containing a spinning rotor connected to a shaft. The shaft is radially disposed in a wedge-shaped gap formed by a pair of supporting disks and is driven by means of a tangential belt. The belt is biased in the direction of the shaft by means of a pressure pulley arranged on a movable arm that is biased by a spring. The machine has at least one movable servicing apparatus that can be applied to each spinning unit. The servicing apparatus contains means for exposing the spinning rotor and means for moving the arm with the pressure pulley into an inoperative position.
An open-end spinning machine of the general type is disclosed in German DE-PS No. 23 60 296. The shafts of the spinning rotors of the spinning units are disposed in normal radial bearings. For stopping the spinning rotor, the movable servicing apparatus operates a lever bar system via which the arm with with the pressure pulley is moved to an inoperative position. At the same time, a brake present in each spinning unit is applied to the rotor shaft. In the case of open-end spinning machines used in practice, the rotor shafts, deviating from the construction disclosed in DE-PS No. 23 60 296, are disposed in wedge-shaped gaps formed by supporting disks. In these open-end spinning machines, the brake of the individual spinning units is designed in such a way that it is applied to the rotor shaft from the same side as the tangential belt when the tangential belt is lifted off for the purpose of interrupting the drive. The brake will then take over the securing of the rotor shaft and thus of the whole spinning rotor in its operating position. The brake is applied to the shaft of the spinning rotor next to the tangential belt. Because of the relatively small diameter of the shafts of the spinning rotors, relatively high braking forces must be applied in order to achieve effective braking. These relatively high braking forces result in increased wear of the brake linings. In addition, the diameter of the shaft cannot be decreased which would be desirable in the case of transition to significantly higher speeds. The brake that is applied to the shaft in the axial direction of the shaft also requires a certain space, such that the length of the shaft cannot be decreased at all or cannot be decreased significantly which would be desirable for very high speeds.
An objective of the present invention is the provision of an open-end spinning machine wherein constructive limitations in the area of the bearings of the spinning rotors are decreased. This objective is achieved by providing the servicing apparatus with a brake that can be applied to the rotor and by providing means that secure the spinning rotor in the operating position when the pressure pulley is moved away.
Since the braking of the spinning rotor no longer takes place at the rotor shaft, the space requirements are decreased. Accordingly, the supporting disks can be moved closer together while the rotor shaft, at the same time, can be designed to be shorter. Since relatively high braking forces no longer affect the shaft, it may have a smaller diameter without the danger of unacceptable heating and/or deformation. The braking at the rotor has the advantage that the application of the brake takes place at a relatively large circumference so that the necessary braking force can be lowered. In addition, the brake that is susceptible to wear is part of the servicing apparatus. In the construction, checking or regular maintenance can be carried out much more easily. Means need only be provided for securing the operating position of the spinning rotor which in most cases are not subjected to significant wear.
In an advantageous development of the present invention, the means for securing the spinning rotor in its operating position are part of the servicing apparatus which can be applied to the exposed rotor. These means therefore do not have to be provided for each spinning unit but only for the servicing apparatus. In this development, it is especially easy from a constructive point of view, when the means for the securing of the spinning rotor in its operating position and the brake are designed as a structural component that can be applied to the rotor jointly.
In another advantageous development of the invention, it is provided that the brake contains tong-type grippers which can be applied to the rotor in the radial direction by means of brake shoes. These tong-type grippers may take over the securing of the spinning rotor in its operating position. It is advantageous that the brake shoes have profiling and reach around the profiling of the rotor from the outside. This results in axial as well as in radial securing.
In a further development of the invention, the brake can be applied in an axial direction toward the rotor and the shaft of the spinning rotor is supported by a stop in the axial direction. In this embodiment, the spinning rotor is clamped between the brake and the axial stop so that it is secured in its position. In this case, it is advantageous when the brake, by means of a conically expanding brake lining, in the axial direction, can be applied to the exterior side of the rotor having at least approximately the same conical contour.
In a further development of the invention, the brake is provided with centering elements which in the case of the axial application to the rotor of a spinning unit, engage in counterparts, which are arranged at the spinning unit in a position that is aligned precisely with the rotor plate. By means of this measure, in the case of an application of the brake, an alignment with respect to the rotor is achieved so that this rotor is gripped precisely in its operating position and can be held there.
In a further development of the invention, each spinning unit is equipped with means for fixing the operating position. These means are applied to the shaft of the spinning rotor. In this case, the brake of the servicing apparatus generally must contribute nothing to securing of the spinning rotor in its operating position, even if this is possible as a support. in the case of a simple embodiment of the invention, it is provided that each spinning unit is equipped with at least one stationary stop which is located at a small distance opposite the shaft on the side that faces away from the wedge-shaped gap. In the case of another embodiment of the invention, it is provided that each spinning unit is equipped with a supporting disk that can be applied to the shaft by the servicing apparatus. This disk then takes over the load by means of which the shaft of the spinning rotor is pressed into the wedge-shaped gap when the pressure pulley and the tangential belt for the interruption of the drive are moved away from the shaft of the spinning rotor.
In order to keep the cost as low as possible in this case, it is advantageous when the supporting disk be mounted on holding elements carrying the pressure pulley in such a way that when the means for moving away of the pressure pulley are operated, the supporting disk can be applied to the shaft.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.